The Inflammatory Response

Abstract

The activation and migration of leukocytes during infection or injury and the subsequent systemic physiologic changes that occur characterize the inflammatory response. This response represents the body’s attempt to identify, contain, and eliminate pathogens, but gone awry it is an important source of morbidity and mortality in the pediatric intensive care unit (PICU). The sepsis syndrome, for example, can be thought of not as an overwhelming infection but as the body’s deadly over-reaction to microbial invasion. A great deal has been learned about the mediators and mechanisms of the inflammatory response but surprisingly few therapies have been shown to be effective in controlling it to the patients’ benefit. In fact, mounting evidence suggests that natural or iatrogenic anti-inflammatory counter-regulation can be harmful if not carefully balanced. In this chapter this balance will be explored on both intra- and extra-cellular levels. The discussion will then shift back to the bedside to review the history of immunomodulation in the ICU, describe the impact of intensive care on the inflammatory response, and highlight promising areas of research into the modulation of the inflammatory response. The literature on these subjects, both basic and clinical, is expansive and cannot be covered in an all-inclusive manner. The objective of this chapter, therefore, is to provide an overview of the inflammatory response and familiarization with enough terminology to allow informed reading of the literature and understanding of the relevance of inflammation to clinical practice.